You go to the doctor's surgery to have your blood pressure checked - and it's dangerously high. Does this mean you're an immediate candidate for an antihypertensive drug or, worse, a heart attack?
If your doctor is worth his salt, he should be planning for a full round-the-clock check of your blood pressure, and especially during the night when the level tends to drop dramatically. It's also well known that most people's blood pressure rises when they are in the doctor's surgery.
The 24-hour blood pressure check is now considered to be best practice, even though far too few doctors follow it.
As researchers have reported in a new study, what is found in the doctor's surgery is only part of the picture - and it may be the least reliable part - whereas the amount that blood pressure decreases in the night is probably the most significant.
They carried out 24-hour monitoring on 7,458 people, and discovered that night-time blood pressure levels were a far more accurate predictor of a heart attack.
(Source: The Lancet, 2007; 370: 1219-29).